Messages in this thread | | | Date | Sat, 10 Sep 2011 10:51:49 -0400 | From | Nitin Gupta <> | Subject | Re: [PATCH 5/5] zram: Set initial disksize to some default value |
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On 09/09/2011 08:42 PM, Greg KH wrote:
> On Fri, Sep 09, 2011 at 08:18:56PM -0400, Nitin Gupta wrote: >> On 09/09/2011 07:12 PM, Greg KH wrote: >> >>> On Fri, Sep 09, 2011 at 07:01:04PM -0400, Nitin Gupta wrote: >>>> Currently, we set initial disksize as 0, which forces >>>> user to write some value to corresponding zram device's >>>> sysfs node, before the device can be used. Now, we avoid >>>> this step by providing some default size initially. >>>> >>>> To change the disksize, user must: >>>> - Reset disk. >>>> Ex: echo 1 > /sys/block/zram0/reset >>>> (NOTE: disksize is set to the default value after reset) >>>> >>>> - Set new disksize. >>>> Ex: echo $((256*1024*1024)) > /sys/block/zram0/disksize >>> >>> So, what tools just broke with this change? >>> >>> And where is the sysfs file documentation change that should go along >>> with this? >>> >> >> >> This change does not change any sysfs names or behavior, so does not >> break any scripts that assume the current behavior. I also verified that >> sysfs documentation (ABI/testing/sysfs-block-zram) need not be changed >> and same with drivers/staging/zram/zram.txt. > > Huh, you just said the behavior changed as described in your comment > above. You said the user no longer has to do a step to accomplish > something. What happens if they do do that after this patch? >
The current documentation states that:
"" (from drivers/staging/zram/zram.txt) 2) Set Disksize (Optional): Set disk size by writing the value to sysfs node 'disksize' (in bytes). If disksize is not given, default value of 25% of RAM is used. ""
So existing code did not correctly implement this behavior -- user had to set a disksize for zram to be usable. With this patch, the code now behaves exactly as described in documentation. So, we now avoid the extra step of setting a disksize as documented. The user can still, of course, set another disk value if needed.
So, in summary, no documentation changes are required with this change. I will also add this explanation in changelog when submitting v4 patches.
Thanks, Nitin
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